This invention relates to a method of fusing two or more pieces along an edge to produce a volume. More particularly, this invention relates to a method of fusing two or more pieces along an edge by adding an activating agent which dissolves and mixes with a component on the pieces, and thereby causes the edges of the various pieces to fuse together. The method of this invention is particularly useful for producing bound periodicals and magazines.
A magazine or a periodical typically comprises a stack of individual sheets or folios bound together. If individual two-sided sheets are bound together, then each individual sheet represents two pages in a bound magazine or periodical. If a stack of two-sided double spread sheets, termed folios, are bound together, then each folio represents four pages in the bound magazine or periodical.
A common method for producing magazines or periodicals involves collating a stack of sheets or folios and holding the stack together with a staple, commonly referred to in the art as a pin. The use of a pin limits the thickness of a periodical or a magazine. Typically, a stack of folios is collated to produce a signature, and pinned together. A typical pinned magazine comprises a single signature pinned along the center folio. The center folio, which is also referred to as the center spread, represents the midpoint of such a magazine. The center spread is unique in that it has the maximum continuous printable area in the typical magazine. The availability of more than one center spread in a magazine would significantly enhance the value of a magazine. But in the typical pinned magazine comprising a single signature as described above, there is only one center spread available. Furthermore, in the single center spread of such a magazine, the pins are visible along the center. The pins can obscure the printed matter or distract the reader.
Another common method for producing magazines or periodicals involves the use of a hot-melt adhesive. Typically, a hot polyurethane adhesive is used in this method. To bind a stack of individual sheets, a hot polyurethane adhesive is applied to an edge of the stack, and the bound edge is allowed to cool and dry. The time required for cooling and drying the bound edge is often long. As a result, the rate at which the bound magazines or periodicals are produced may be relatively slow. Secondly, the adhesive adds to the thickness of the bound edge. This can be a detrimental feature in commercial magazines and periodicals wherein the standards of aesthetics and form are extremely competitive and high.
Hot-melt adhesives are also used to bind a stack of signatures, wherein each signature comprises two or more folios. In a typical method for binding a stack of signatures using an adhesive, the edge of the stack that is to be bound is cut to expose the edge of each individual sheet to the adhesive. As a result, the advantage of having a center spread in each signature is lost because the resulting volume comprises individual sheets bound at an edge with no center spread. Alternatively, the folios of each signature are bound together in known ways as the signature is assembled, and then the signatures are bound together by the hot-melt adhesive. While this technique may preserve the various center spreads, it still has the drawbacks associated with the use of hot-melt adhesives.
It would be desirable to be able to produce a magazine or a periodical having more than one center spread.
It would also be desirable to produce a magazine or a periodical wherein the center spread has no visible pins, thereby enhancing the effect of the printed matter.
It would further be desirable to fuse a stack of sheets along an edge with a minimal waiting time for cooling and drying the bound edge.
It would still further be desirable to minimize the thickness of the bound edge in the resulting magazine or periodical.
It would yet further be desirable to fuse a stack of signatures along an edge without cutting the signatures, and thereby retain the center spreads in each signature.